You can't take gambling losses, but you can offset winnings with losses (not below $0).
Here is how to add your W-2G in TurboTax Online:
- Click on Federal Taxes, Wages & Income, scroll down to Less Common Income > Gambling Winnings > Start or Revisit
- Enter the information from the W-2G.
Here is some more information you may find helpful: How to Pay Taxes on Gambling Winnings and Losses
